From a systems biology standpoint, Dictyostelium is a fascinating genus. Systems biology refers to the interdisciplinary area of biology that uses a holistic computational and mathematical models to describe biological systems. These can be the systems within an organism, as well as interactions between organisms as a system. It also discusses emergent properties, tissue and organ properties and organisms functioning as a theoretical system.

The genus Dictyostelium exists in the order Dictyosteliida, also known as social amoebae.  For many years Dictyostelium, specifically D. discoideum, has been a favorite subject of systems biologists because of its uni- and multicellularity. When members of the Dictyostelium genus begin life, they are a single celled haploid, and have a very standard eukaryotic anatomy. They will usually remain in this vegetative state as long as bacteria living in the soil, their main food source, remains plentiful enough and they will divide by mitosis periodically. However, once food becomes scarce, members of this genus will enter a starvation state, which forces them to transform into their multicellular state. The cells will become able to aggregate, forming a mound, a first finger, then they become multicellular slugs, which migrate from their low-light environment to find light. Once they find enough light, they transform into culminates which become a fruiting body with a long stem and a mass of spore cells on top, ready to be distributed. It is this very process, wherein a unicellular organism is able to aggregate and become a multicellular organism for reproduction, that is so fascinating in the realm of systems of biology. This is because there are now multiple levels to the system. It is no longer single cells and their anatomical systems as well as cells interacting and competing for resources, but there are now systems of cells forming various multicellular organisms, and these multicellular organisms competing to get the best resources and spread their spores efficiently.

What’s even more fascinating is that members of the genus Dictyostelium are able to adapt to their environments in the multicellular state by altering their unicellular counterparts. In a study by Bonner and Slifkin in 1949, “A Study of the Control of Differentiation: The Proportions of Stalk and Spore Cells in the Slime Mold Dictyostelium discoideum”, the researchers found that when the temperature of the environment of D. discoideum was altered, the fruiting body was also altered. While there was no significant reaction to temperatures being lowered, when they raised the temperature, they found that the proportion of stem cells in the fruiting body decreased, especially when the temperature decreased drastically. This means that the multicellular organism changed its anatomy by altering the state of the unicellular organisms, dictating them to be spore mass cells more often than stem cells. The ability of unicellular organisms to change based on their environment and thus optimize their multicellular forms is incredibly helpful, and magnificently strange. This is the reason that members of the genus Dictyostelium have always been, and continue to be, a fascinating subject for systems biologists.